1. Field of the Invention
The present invention relates to an apparatus for serial collection, storage and processing of biopsy specimens. The device cuts and captures a biopsy specimen with a closely defined size to permit serial entry into a removable distal storage cassette for in situ chemical, biological or genetic testing by immediately reacting with the biopsy specimens before metabolic changes, degradation or contamination can occur or for fixation, staining and other processing and analysis. The cassette may be optically transparent for physical analysis of the tissue without removal from the cassette after separation from the biopsy instrument. Prior to biopsy the open tube shaft with a side arm permits fluid sampling, irrigation, and injection of tissue stains or radiopaque contrast agents.
2. The Prior Art
It is often necessary to obtain tissue samples for examination from deep within structures. These samples can only be retrieved by catheterization methods using endoscopic or fluoroscopic control, or by blind palpation. The biopsy devices previously used for these techniques removed 1 to 4 specimens that were retrieved by removing the biopsy instrument from the patient, and placing the specimen in a container of fixative solution labeled with the biopsy site and patient identification. During this process of acquisition and collection minute specimens were frequently lost and are always contaminated by handling and passage through the endoscope instrument channel. Furthermore during acquisition the staff is exposed to potentially infectious human tissue and toxic fixatives.
The biopsies obtained in each pass were processed in a batch, since the minute pieces could not be easily separated. Multiple biopsy passes were required because of the limited storage capacity of the biopsy instruments and the need to identify the origin of each biopsy sites. Consequently, biopsies from different anatomic sites were handled separately, thus requiring considerable effort and expense. After each biopsy pass the biopsy(s) must be removed from the biopsy instrument and placed in a labeled fixative container. The biopsy instrument was washed to remove fixative and returned to the endoscopist for passage through the endoscope for the next biopsy. This prolonged the procedure and could cause it to fail, if the position of the biopsy instrument could not be reacquired during the repeated passes of the biopsy instrument through the endoscope. This complexity prolonged the endoscopic procedure and increased the quantity of sedative administered to the patient, risk and cost.
The containers for each patient were then transported to the laboratory where each container was serially opened and each specimen batch transferred to individual numbered cassettes that were recorded for later identification. The cassettes were then processed for examination. The processed specimens were then sliced, stained and mounted on labeled slides for microscopic examination. The specimens in each container must be processed and mounted on slides separately to maintain identification. This was particularly important when the distribution and extent of a cancer was being mapped to determine therapy and to prevent errors in reporting.
During this complex handling process, small specimens may be lost or damaged. At each stage of handling, the staff is exposed to infection from the biopsies and fixative. This is particularly true when the unfixed specimen is removed from the sharp biopsy instrument before fixation. The staff is also exposed to solvent vapor from the fixative at each transfer step of processing. The solvents may be allergenic or carcinogenic. This tedious, labor intensive process is expensive in staff required, time, equipment and laboratory space.
Specimens needed for chemical, biological or genetic testing require additional biopsies that must be handled separately. These specimens were contaminated by fluid and tissue in the track traversed to obtain the biopsies and within the channel of the endoscopic instrument. The delay in acquisition and contamination of the specimens limit the accuracy and reliability of the subsequent analysis. This disability may be severe when genetic or biological testing is needed.
The prior art described in the spring based multipurpose medical instrument in U.S. Pat. No. 5,782,747 to Zimmon, the disclosure of which is herein incorporated by reference, obviates the use of cumbersome metal shafts and coverings that occupy the space needed for specimen storage. Standard jaw fulcrum biopsy devices require a stiff shaft to prevent kinking and binding within the endoscope when the actuator cable(s) is pulled to close the biopsy jaws and then held to maintain jaw closure when removing the device and biopsy from the endoscope or access passage. The combined stiffness of the shaft and pull on the actuator cable(s) straightens the biopsy device and endoscope. This action moves the endoscope and biopsy device away from the biopsy site, limits maneuverability and prevents rapid serial biopsy of the target site. This stiffness and uncontrolled motion also risks trauma to the biopsy site and limits access in curved lumens. A further limitation of stiff shafts is that they reduce the options for carrier instrument flexibility and maneuverability.
The closing force of a traditional forceps biopsy instrument is limited by a shaft length ranging from 100 cm to 220 cm and the multiple curves traversed within the endoscope that must conform to a lumen. Because of these disabilities, endoscopic biopsy forceps that are 5 to 9 French in diameter rip the mucosal biopsy from the muscularis mucosa. This gives a biopsy that is larger than the forceps cup and varies in size. Furthermore, tissue distortion from biopsy trauma makes histopathologic interpretation difficult because of crush and shear artifacts. These artifacts result in false positive and false negative histopathologic interpretations of biopsy specimens leading to an incorrect diagnosis.
U.S. Pat. Nos. 5,685,320 and 5,782,747, both to Zimmon, both of which are herein incorporated by reference, solve this problem by sharply cutting biopsies of defined size that are suitable for passage through the tube shaft to an external receptacle. In U.S. Pat. No. 5,685,320 to Zimmon, herein incorporated by reference, the lateral biopsy device uses a precise distance between the central actuator wire and the cutting blade to control biopsy depth. Consequently, biopsy depth is less than one half of the shaft diameter. Actuator wire movement that limits the length of the cutting notch controls biopsy length. Width of the tangential biopsy is less than one half the tube shaft radius. The cut biopsy is then captured within the tube shaft at the time of biopsy and therefore available to move into the collection cassette.
In U.S. Pat. No. 5,782,747, the spring based multi-purpose medical instrument compresses folded spring sharp biopsy cups by sliding the tube shaft over a folded spring. The actuator wire only serves to hold the folded spring blade in the biopsy position during biopsy cutting. The closed biopsy cups both cut and capture a biopsy of controlled size that is matched to the tube shaft and therefore available to move into the storage cassette.
The motive force of suction or fluid pressure propels the precisely cut biopsy from either device into the proximal collection cassette as described in U.S. Pat. No. 6,071,248 to Zimmon, which is herein incorporated by reference. In U.S. Pat. No. 6,322,522 to Zimmon, which is herein incorporated by reference, the spring based multi-purpose medical instrument is modified to capture biopsy specimens in a removable cassette or cassettes at the proximal end of the biopsy instrument for immediate processing and analysis without removing and destroying the biopsy instrument to form the cassette. This improvement allows real time specimen analysis during the biopsy procedure and the use of a relatively expensive reusable or reprocessable biopsy instrument.
The serial collection, storage and processing of multiple specimens within a biopsy instrument yields a great savings of time and effort in processing the biopsies, as well as preventing specimen loss or damage during handling and protecting staff from infectious material and toxic fixatives. This goal is facilitated by applying redundant methods for forcing the minute biopsy specimens into a storage cassette of the biopsy instrument and by minimizing the operating parts of the biopsy instrument to maximize the storage volume.
Although the prior art has made safe efficient biopsy deep within the patient possible, the need for additional improvements remains.